PlantFiles: Baseball Plant, Klipnoors, Sea Urchin
Euphorbia obesa

Zone 9b Coastal Otago, New Zealand
I grow mine indoors on a half-shaded windowsill and its about 10 years old and pushing 20cm tall. Ive learnt my lesson about exposing many cacti to our insane UV levels without mitigation- sunburn a go go!
Im not sure if the brown streaks common on the ridges of this species is a feature of the plant, a product of exposure burn or mite damage- everyone seems to have a different story.
Mine flowers madly at almost any time of year but is obviously a batchelor male and thus no babies- doh. I am very fond of it- its a crazy little tartan dinosaur demanding no special treatment.
I find all euphorbias more rot-proof than a lot of the true cacti- in my initial ignorance I have overwatered many of the poor little buggers and theyve all survived.
I fertilize just with whatever soluble junk I have to hand. Some claim they are frost tolerant and I have other, less-treasured euphorbs outside all year and they seem fine, but I dunno.... I can see this guy succumbing and personally wouldnt recommend you risk a mature specimen.
Besides, theyre better company inside :-0

I recently got one of these and picked out a female with a couple seed pods on top figuring I could get lucky and get several plants for the price of 1. Once the seed pod fell off (it didn't explode for me), I let it dry and opened it to get the three (large) seeds out. I planted them in a small pot in a baggie like one would do for cactus and placed them on a warm aquarium hood. In 3 days I had 100% germination. That gets an A+ on ease of propagation.

I'm keeping them indoors until spring because my version of 9b is extremely wet in the winter, though most C&S do okay under an eave where they stay dry. I'll experiment with some seedlings under the eave and in a cold frame next winter.

I like this plant because it is a wonderful example of convergent evolution. I keep it next to an astrophytum asterias with a sea urchin shell in the pot to form a neat little look-alike collection.

I tried to grow this plant outdoors in Thousand Oaks California (a very 'cold' zone 9b) but no luck.. However, it does great in Simi Valley (better soil), also 9b, and I have no problems with it here in Tarzana zone 9b-10a. Does rot easily if overwatered in winter, though. Slow growing plant, but eventually can get up to 1' tall, and sometimes will 'branch' or sucker creating very odd looking clusters of spheres. Some crested and monstrose forms out there that are great looking neoplastic appearing potted plants.

Strange how this has a common name of 'cactus', but is actually in the Euphorbia family.......hmmmm.
Still cool lookin' anyway.

This plant is dioecious. The sex of the plant can be identified when they flower. The female has three protruding stigma on which the pollen grains stick, whereas the mail has a hairy like center covered with yellow pollen. Once pollinated the femaile plant produces fruit containing 3 seeds each. The plant elongates as it gets older, becoming a column rather than a sphere.

I had mine out in the direct sun and it looked like it was about to bloom, I saw a little of a yellow bloom then it was gone. This happened a couple of times. So I just bought it back inside. It started getting brown around the edges,close to the top of the pot. Usually I do not have my plants out in the sun because I am afraid of aphids or mealy bugs. So unfortunately they never bloom. But when I bought this it had just started blooming and I decided to let it get all the sun it could.

Preffers a warm position in full sun, otherwise it may lose its lovely rounded shape and even rot! Makes nice hybrids with E. valida and E. mellanoformis. Plants are either male or female, never both.